I've been through thousands of #400's in my AR's and have never had a slam fire, punctured primer, blown out primer, or any other primer issue. They work fine in my 5.56's, my 6.8spc, and my .300 ACC Blackout.

Your response is a common one, but it's still just anecdotal evidence as the next guy's gun may not have the same relationships between chamber, boltface and firing pin protrusion as yours does. Also, I've counted slamfires at big matches before and estimated there seem to be about one for every 15-20,000 rounds downrange or so. Assuming that number applies to non-match guns as well as match guns, you'd have to shoot through a couple or three AR barrels to have an even chance of having one, so maybe you just haven't had your turn yet.

I shot the sensitive Federal 210M in Garands and an M1A for years without an incident, so you'd think I'd share your thinking on this, but I no longer use them in those applications. I look at slamfires and out of battery fires like head-on collisions in cars. I've never had one, but that doesn't mean they can't happen or that measures to reduce their likelihood, like dividing highways, won't prevent some. I don't want to be in the position of having one of the rare OOB fires that injures a junior shooter on an adjacent firing point and not think I'd taken every prudent precaution to avoid it. I also don't want the attorneys his parents hire discovering I haven't taken every known possible preventive measure to prevent its occurrence.

The CCI #41 is identical to a CCI 400 magnum small rifle primer, except that the anvil is shorter so more firing pin crush is needed to set it off.

The TulAmmo KVB556M is a much less expensive Russian made NATO spec primer. I don't know the mechanism of sensitivity control in those, but can tell you they give me lower velocity extreme spread than the #41's do. They take a little more force to seat, but otherwise are great performers. They are also a magnum primer.

The new entry in the field is the Federal GMM205MAR, which is not a magnum primer. An email to Federal got me the information that it is identical to their mild and very consistent GMM205M, except that they've made the cup thicker as their sensitivity control.

I only have 7 ar's and have been shooting and reloading for them for over 10 years now. Been though thousands of rounds so far. I guess I'll just call myself lucky for now. If I ever do get a slam fire I'll consider switching, till then I keep using what I have.

only have 7 ar's and have been shooting and reloading for them for over 10 years now. Been though thousands of rounds so far.

Yes, that supports what I said: your personal experience just is not statistically sufficient to prove the value of the harder primers one way or the other. By comparison, a match at Viale range might have 300 rifles shooting 15,000-25,000 rounds over the course of the day (depending on the match), and there might be one slamfire all day long. You'd probably want to see at least fifteen or so slamfires to get a better statistical sense of how often they really happen, so we're looking at shooting maybe a quarter million rounds of standard primers against that same number of military hardness spec primers among a hundred rifles to get a realistic comparative sense of the level of immunity the military primers actually offer.

Fortunately for the statisticians, the military routinely fires millions of rounds retesting guns for barrel accuracy qualification, and they investigate every failure carefully to find the cause. That feedback helped develop their primer specs. Given their baseline data advantage, I see no reason to disbelieve their specs reflect the best design safety and reliability practices with their own weapons.

I suppose if it was just my own neck I was worried about, I might do the same as you do, based on my experiences with the Garand and M1A. The guy behind the gun is seldom fatally injured by a slamfire or an OOB fire's gun disassembly. Instead, it's the guy a wild round flying over the berm manages to find or the fellow on your right getting a piece of your boltface in his temple that you have to worry most about. That's the reason I switched to military spec primers. That's where the liability resides, as well.

I also think using these less sensitive primers is especially prudent for the novice reloader. He's more likely to have a high primer, which is generally agreed to be the most common cause of slamfires and OOB fires for handloaders. He's also likely to be a less experienced shooter, and so is more likely to suffer a lapse in attention in keeping the muzzle directed at the berm during loading. All in all, he's the one most likely to be the beneficiary of the added protection of the lower sensitivity.

I use the Wolf. Powder Valley had them listed as "5.56 primers" but the box says "small rifle magnum" so whether the wolf is milspec or not I don't know. But they seem to shoot quite well, and a lot of high power shooters are also using them.

They have worked so well I'm thinking about getting some Tula or Wolf 7.62 spec primers for my large rifle primer needs. For a third the cost of CCI-BR2s I don't think I would be unhappy unless my groups really opened up.

Jimro

__________________
Machine guns are awesome until you have to carry one.

No. They are the same exact primer except for the brass anvil (the little tripod you see upside down in the primer). As long as you have adequate firing pin energy you should be good to go.

Jimro,

TulAmmo has both the KVB-556M and the KVB-223M available as magnum rifle primers. The former are the NATO spec primers. I bought 5,000 of them and 5,000 KVB-762 primers last year when Graf & Sons had them on sale for $16/1000 in that quantity. What I've noticed is the labeling of the cartons of 1000 and the individual 100 packs don't have complete information on them. Only the outside carton of the 5000 gave the actual Tula Russia plant's labeling (that's where I picked up the hyphen after KVB) and showed what the exact primer was inside. If you got such a carton, that number might be on it. If you bought fewer than that, the labeling may not be telling you what you want to know. You might be able to call Wolf and ask which of those two numbers are actually in the boxes.

As near as I can tell, the KVB-762 and KVB-556M both are beating all the domestic primers I have for muzzle velocity consistency with stick powders. I haven't done a run-through with spherical propellants yet. These primers are a little harder to seat than I'm used to, so I run even my non-crimped brass through either my Dillon Swager or apply a Wilson primer pocket reamer to them to get maximum room in the pockets before using them.

I still have the 5k sleeve that my primers came in, so I'll check. It would be interesting to find out if there is any functional difference between the KVB-556M and KVB223M such as cup thickness or primer composition.

Without anything more scientific than a "residue test" on my Lee Pro1000 priming system, the Wolf primers seem to be loaded with a Lead Styphnate compound (yellowish dust).

I know the Federal GMM primers still use Lead Styphnate as the priming compound as they can control the "flame" better than the newer "green" PETN priming compound. If the Russians never transitioned to PETN that would explain why their primers are providing "match grade" performance by comparison.

Jimro

__________________
Machine guns are awesome until you have to carry one.

Currently it's the KVB-556M. Powder Valley has the Tula Primers, as does Graf & Sons.

Jimro,

If you look at the MSDS sheets, CCI and Remington and Winchester and TulAmmo all use normal lead styphnate (aka, lead trinitroresorcinate or lead styphnate), while Federal uses basic lead styphnate (aka, lead hydroxide 2,4,6 trinitroresorcinate, or lead styphnate hydroxide). That latter compound is a bit more sensitive, apparently, but it's also used in military primers with sensitivity tempered by cup and/or anvil geometry. Apparently Federal thinks it ignites more consistently. The TulAmmo primers have a compound I don't see in anyone else's primers called monosubstituted potassium styphate. It's in both their standard and non-toxic primers. Perhaps it's their secret to uniformity. I don't know enough about explosive chemistry to guess. Remington has lead trinitroresorcinate in additions to lead styphnate. Winchester has lead thiocyanate in addition to lead styphnate. So more than one lead compound is involved in those two brands of lead-bearing primers.

There's no PETN in any of the primer MSDS's for non-toxic primers that I've found. The compound that substitutes for lead styphnate in the NT primers is DDNP (diazodinitrophenol). It's brissance is higher than lead styphnate's, apparently, because larger flash holes are normally used in large primer versions so they can vent gas pressure fast enough to keep it from backing the cup out of the primer pocket hard and fast enough to pierce. The flash hole in small primer pockets seems to be large enough in proportion to the rest of the pocket that it doesn't need to be modified for this. That's why it's become standard in NT .45 Auto brass to use a small primer pocket, where you used to see a large primer NT .45 Auto cases, but with a 1/8" flash hole. There's a good article on the problem, here.

I use the CCI armory primers for anything that is going to be fired in a semi-automatic weapon that has a free floating firing pin. The cost difference is minimal and worth the reduced risk of a slam-fire IMO.

CCI #41 for 5.56x45
CCI #34 for 7.62x39, 7.62 Nato, 30-06.

__________________
NRA Lifetime Member Since 1999

"I ask, sir, what is the militia? It is the whole people except for a few public officials." George Mason

I may have to take it back. I finally located a military priming mix that includes PETN (MIL-P-46610E(MU), 3.7.1). Surprised the heck out of me to see it there, as I don't know why they'd want it, but I'm not their chemist. Perhaps it's filling the same roll as TNT and DNT that has been used in some primers in the past, and that is as a fuel for the flame rather than as a sensitizer. I just don't spot PETN in any of the commercial primer MSDS sheets.

I think the PETN is there for the ball powder used in M80 ammunition. Back in the 90's it was known that m80 ball was experiencing ignition delays which could be problematic in the m134 minigun. Various primer/powder combinations were tried, and the recommendation was go to with the WC846FS (Flash Suppressed) powder as it showed better ignition with either the #43 or #34 primers.

I'm still learning about powder/primer combos, trying to figure out what works best. My experience with ball powders has been very good accuracy wise, so I looked a little deeper into where that "stick powders are more accurate" common wisdom came from, and that led me down the path of primers. Evidently the lots of match ammo loaded with 4895 were more accurate than the lots loaded with 846, and looking back with hindsight it makes sense that the powder/primer interface with 846 was a tad on the poor side.

I'm thinking that the whole "stick powders are more accurate" wisdom can be summed up in the story of the primers. Stick powders are generally easier to light, so you can have a smaller (hence more consistent) primer charge, which leads to less initial pressure variation (and more consistent timing). The powder isn't the culprit, the primer is the culprit as far as I can tell.

The problem is making a primer hot enough to light off ball powder consistently, that is itself consistent enough for accuracy. I think some of the new "green" primers will get there and we'll keep seeing the accuracy difference get slimmer and slimmer....

Jimro

__________________
Machine guns are awesome until you have to carry one.

Sounds like the military solution, then. Alan Jones said CCI reformulated their magnum primers to optimize them for spherical propellants in 1989, but they apparently get the heat up using barium nitrate, as their MSDS has no PETN. Barium oxidizers do burn hot. I remember they were necessary to get thermit to ignite consistently when I was playing with that stuff in the 60's.

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